It is globally acknowledged that the depletion of natural energy resources, environmental issues arising from the use thereof and the lack of alternative energy resources are but some of the issues that impact the profile of the energy landscape of the future. To date, natural energy resources continue to be used for the generation of different energy forms. For example, the thermal energy generated from fossil fuels such as oil, gas and coal is converted to other energy forms such as electrical, motion and so on. However, such natural energy resources, and fossil fuels in particular, are becoming scarce, cannot be replaced and/or detrimentally impact the environment. Nuclear energy has been used as an alternative energy form to the aforementioned energy resources. In particular, nuclear fission has been used for the generation of heat and electricity. However, there are short-term risks such as incidences associated with nuclear fission as well as long term issues such as storage and/or disposal of radioactive waste resulting from nuclear fission.
In order to address the above-described issues and/or to provide alternative energy resources, investment, development and research into renewable energy resources such as, for example, solar and wind power, is being done. An advantage associated with renewable energy resources, and from the viewpoint of sustainability, is that they may be considered to be abundant given that, thus far, there is no known limit on the life expectancy of the sun. However, there are some issues associated with renewable energy resources, which restrict them from providing a suitable alternative to and/or completely replacing fossil fuels for the generation of energy. One such issue is that renewable energy resources are time-variant in their occurrence—the wind does not always blow and the solar irradiance depends on the time of the day and on cloud movement. A further issue is that renewable energy resources may be area-specific in that they may occur more abundantly in some areas compared to others, such as, for example, coastal regions and deserts, which may be far away from the demand of such resources, thereby necessitating the consideration of transport issues to the location(s) of the demand.
With respect to the consumption aspect of the energy chain, demand for energy may also be variable and random, albeit with differences from the variability and randomness with which energy is generated using renewable energy resources. To facilitate the alignment of energy demand/consumption with energy supply/generation, particularly where renewable energy resources are used for the energy supply/generation, energy storage devices may be used and/or considered. However, for certain energy forms, such as, for example, electrical energy, it may be a challenge to provide energy storage devices with sufficient capacity, if at all. In this regard, although pump storage plants may provide a solution, they are usually implemented in certain terrains such as mountainous regions and require access to water. Other methods such as, for example, hydrogene extraction and compressed air have associated technical limitations and so are not widely used. As for electrical accumulator technology, it is costly and may be considered to have inadequate storage density, thus space and other resources may have to be facilitated for its implementation in a realistic energy chain scenario.
Some proposals have been made to facilitate alignment between power generation and power consumption/demand. Reference is made to the document titled, “Pacific Northwest Gridwise testbed demonstration projects: Part i. Olympic peninsula project”, published in the Technical Report PNNL-17167, Pacific Northwest National Laboratory, October 2007 by D. J. Hammerstrom et. al and also to the document titled, “Pacific Northwest Gridwise testbed demonstration projects: Part ii. Grid-friendly appliance project”, published in the Technical Report PNNL-17079, Pacific Northwest National Laboratory, October 2007 by D. J. Hammerstrom et. al. These documents publish the investigation conducted in the Pacific Northwest Gridwise project where price incentives were coupled to the generated power and individual electrical appliances could react—momentarily—to power shortages, where a power shortage was observed by a reduced grid frequency, this scenario highlighting how the grid frequency may serve as a universal indicator of the power present in a power grid. The Pacific Northwest Gridwise project is concerned with the alignment of power consumption with power generation rather than aligning energy consumption with energy generation, that is, only current/power decisions are addressed rather than the attainment of energy goals by the provision of power over a given time-period.
Reference is now made to the Danish EDISON project as documented in, “Electrical Vehicle Fleet Integration in the Danish EDISON project—A virtual power plant on the island of Bornholm”, published in Proc. IEEE Power & Energy Society General Meeting 2010, Minneapolis, Minn., USA, Jul. 25-29, 2010, also available at: URL:domino.research.ibm.com/library/cyberdig.nsf/papers/9C976F3545EA6E EE852576AF003208EE/$File/rz3761.pdf, by C. Binding et. al, and “Introducing Electrical Vehicles into the current electricity markets”, EDISON Deliverable D2.3, Version 3, C. Hay, M. Togeby, N.C. Bang (Ea Energy Analyses), C. Sondergren (Danish Energy Association), L. H. Hansen (Dong Energy), May 25, 2010, URL:www.edison-net.dk/{tilde over ( )}/media/EDISON/Reports/Edison Deliverable2.3Version3.0.ashx. Like the Pacific Northwest Gridwise project, the Danish EDISON project, is also based on price signals that are coupled to power generation and works only in the power dimension rather than in the energy dimension.
Another proposal to facilitate addressing the misbalance between power generation and power consumption can be found in the document titled, “Powermatcher: multiagent control in the electricity infrastructure”, published in the Proceedings of the fourth international joint conference on Autonomous agents and multiagent systems, pages 75-82, ACM 2005 by J. K. Kok, C. J. Warmer and I. G. Kamphuis. In the PowerMatcher system, the demand aspects in the power chain hierarchically express their power demand and pass their bids to the generation entities, that is, power generation sources. If mismatching between bids and offers are detected, an auctioning approach to find a feasible bid/offer relation is taken. The PowerMatcher system is organised hierarchically and so it may be scaled, but it has increased real-time communication requirements in order to support an auction-style balancing between power supply/generation and power demand/consumption. Like the Pacific Northwest Gridwise project and the EDISON project, the Powermatcher system operates in the power dimension rather than the energy dimension, i.e. there is no guarantee that sufficient amounts of power are delivered to a demand unit over a given time-period and, thus, in the event that a price quoted in a bid/offer in respect of a given demand unit is considered to be relatively high, no power will be fed into that demand unit and so it will not accumulate energy. In this case, and for example, where the demand unit is embodied by an electrical appliance such as the battery of an electrical vehicle, it will remain uncharged and, if it is a hot-water boiler, then it will not be heated.
Reference is now made to the document titled, “Hierarchical model predictive control for resource distribution”, published in Proceedings of the 49th IEEE conference on decision and control, Atlanta Ga., USA, December 2010, IEEE, by Bendtsen et. al wherein a hierarchical concept using aggregation towards a high-level controller is proposed. Like the above-described documents, this disclosure is concerned with the alignment of power generation with power consumption rather than working in the energy dimension to fulfil an energy goal. Whilst energy constraints have been expressed in terms of the maximum and minimum total energy that can be stored in a device, these terms are static and do not reflect the time-varying need of stored energy as related to energy consumption and inflowing power/energy.